Start Potassiu m argon dating

Potassiu m argon dating

The Ngauruhoe area was accessed from State Highway 47 via Mangateopopo Road. Care was taken to ensure correct identification of each lava flow and that the samples collected were representative of each flow and any variations in textures and phenocrysts in the lavas.

Ngauruhoe in the Taupo Volcanic Zone, produced andesite flows in 19 and avalanche deposits in 1975.

Potassium-argon “dating” of five of these flows and deposits yielded K-Ar model “ages” from Ar* content.

503–525 (1998), and is reproduced here with the permission of the Creation Science Fellowship of Pittsburgh ( Ngauruhoe is an andesite stratovolcano of 2291 m elevation, rising above the Tongariro volcanic massif within the Tongariro Volcanic Center of the Taupo Volcanic Zone, North Island, New Zealand (fig.

1).12 Though not as well publicized as its neighbor, Mt.

K-Ar dating is based on measurement of the product of the radioactive decay of an isotope of potassium (K), which is a common element found in many materials, such as micas, clay minerals, tephra, and evaporites, into argon.

The technique known as potassium-argon dating is used to date old lava flows.

By February 12 the flow had ceased moving, subsequent mapping placing its volume at about 575,000 m34 Further explosive pyroclastic (ash) eruptions followed, reaching a maximum about February 19-21 . The eruption from May 13, 1954, to March 10, 1955, began with explosive ejection of ash and blocks, although red-hot lava had been seen in the crater five months previous.35 Fig.

3 shows the distribution of those 1954 lava flows that are still able to be distinguished on the northwestern and western slopes of Ngauruhoe.

A survey of anomalous K-Ar “dates” indicates they are common, particularly in basalts, xenoliths, and xenocrysts such as diamonds that are regarded as coming from the upper mantle.

In fact, it is now well established that there are large quantities of excess K and not yet outgassed.

Ruapehu (about 12 km to the south), Ngauruhoe is an imposing, almost perfect cone that rises more than 1000 m above the surrounding landscape.